Minerals – Earth’s JewelsMinerals – Earth’s Jewels

SWBAT identify the difference between SWBAT identify the difference between a mineral and a rock; describe the a mineral and a rock; describe the properties that are used to identify properties that are used to identify

mineralsminerals

What is a mineral?What is a mineral?

• Minerals – inorganic, solid materials found in nature.

• What does inorganic mean?– It was not formed by plants or animals

• Rock – made up of two or more minerals.

What is a mineral?What is a mineral?

• How do minerals form?– Minerals form from melted rock material,

called magma, that cools

• Precipitation – Water drops out minerals that it cannot hold

Properties of MineralsProperties of Minerals

• Crystals– Crystals have an orderly pattern of atoms,

arranged in a repeating pattern

Properties of MineralsProperties of Minerals

• Cleavage and fracture– How to a mineral breaks

• Cleavage – Minerals break into smooth planes

• Fracture – Minerals break roughly with jagged or rough

edges

Properties of MineralsProperties of Minerals

• Color – This is the least reliable property of minerals.

Colors can be misleading (gold and pyrite), and some minerals come in many different colors.

Properties of MineralsProperties of Minerals

• Streak – Scrape a mineral across an unglazed

porcelain tile and the color it leaves is its streak. Streak does not always match the color

• Luster– Describes how a mineral reflects light– Shiny, dull, pearly, etc.

Properties of MineralsProperties of Minerals

• Hardness– Mohs scale gives the hardness of each

mineral– What it can be scratched by shows how hard

it is

Properties of MineralsProperties of Minerals

• Specific Gravity– Similar to density– Ratio of weight of the sample to an equal

volume of water

Properties of MineralsProperties of Minerals

• Other properties– Magnetism – Smell– Reaction to chemicals – Visual distortion– Taste

Common MineralsCommon Minerals

• What do we call the common minerals that make up rocks?– Rock forming minerals, which are mostly

silicates (they contain silicon and oxygen)

• Gem – Minerals that are rare and can be cut and

polished to give them a beautiful appearance

• Ore – Minerals that are mined for a profit